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-rw-r--r--kernel/sched/fair.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c11e36ff5ea0..201be782b5b3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1000,7 +1000,7 @@ struct numa_stats {
*/
static void update_numa_stats(struct numa_stats *ns, int nid)
{
- int cpu;
+ int cpu, cpus = 0;
memset(ns, 0, sizeof(*ns));
for_each_cpu(cpu, cpumask_of_node(nid)) {
@@ -1009,8 +1009,21 @@ static void update_numa_stats(struct numa_stats *ns, int nid)
ns->nr_running += rq->nr_running;
ns->load += weighted_cpuload(cpu);
ns->power += power_of(cpu);
+
+ cpus++;
}
+ /*
+ * If we raced with hotplug and there are no CPUs left in our mask
+ * the @ns structure is NULL'ed and task_numa_compare() will
+ * not find this node attractive.
+ *
+ * We'll either bail at !has_capacity, or we'll detect a huge imbalance
+ * and bail there.
+ */
+ if (!cpus)
+ return;
+
ns->load = (ns->load * SCHED_POWER_SCALE) / ns->power;
ns->capacity = DIV_ROUND_CLOSEST(ns->power, SCHED_POWER_SCALE);
ns->has_capacity = (ns->nr_running < ns->capacity);